Although the totally automatic machine tools used in the market nowaday such as computerized numeric-controlled (CNC) milling machines or computerized numeric-controlled (CNC) lathes etc. are very convenient to the operators, the feed path or speed of the machine tools is set by the program. When it comes to incorrect path or improper speed coded in the program, it often causes waste of machining blanks or delay in the machining time. This kind of situation occurs mostly on the fine finishing process in the post-stage of machining work.
However, the post-stage of machining needs only some simple actions such as precisely modifying a circular groove or machining a fillet. It will take a long time and may even damage the original semi-finished products whenever there are some wrong actions if we were to execute by coding an automatic computerized numeric-controlled (CNC) program. What is more, it will be even harder to execute automatically whenever there is a need to perform precise dressing while measuring if the operator requires high precision level. To meet the foregoing requirements, it is more appropriate to machine them manually by the use of the conventional handwheel. But since the foregoing handwheel can not operate two axes at a time, thereby, if one can develop a manually-operated handwheel interpolation-generating device, one can perform bi-axial linear interpolation and biaxial arc-interpolation. Moreover, the interpolation works soon after the handwheel rotates and it stops soon after the handwheel stops, thereby, the machining works can be controlled freely by the skillful hands of the operators.
The block diagram of the handwheel interpolation control system of the prior art as shown in FIG. 1 mainly comprises a operation panel 10 which further comprises a manually-operated handwheel 11 and a manually-operated handwheel multiplicative selection switch 12 where the manually-operated handwheel 11 and the manually-operated handwheel multiplicative selection switch 12 give an output of pulse command in accordance with users' manually operation of handwheel, thereafter, send the pulse command to a position control hardware 20 which, in succession, connect to a servo control hardware 30 and a driven machine 40. In this way, it accepts the control of the users' operating panel to further drive the machine tools and execute our required machining actions. Besides, the operating panel 10 comprises also an axial selection 13 which provides users with the selection of the machining directions along the X, Y and Z axes.
However, the manually actions do not run smoothly. Without going through dressing, two defects on the machined workpieces will show up. Firstly, it will cause bad streaks on the surface if the speed is not a steady one; secondly, when it comes to arc-interpolation, any abrupt increase of pulsatile impulse will worsen the roundness. For example, the U.S. Pat. No. 5,453,674 exposes an interpolation action that uses the pulse output of handwheel by means of graphical interactive method to input the dimension of workpieces. The shortcoming is that it possesses the foregoing defects since the output pulse of the interpolation generator does not go through the action of machining dressing on smoothness, i.e. the manually-operated handwheel will decrease the speed steadiness of the lathe and worsen the surface smoothness of workpiece. Therefore, if one can develop a computerized numeric-controlled (CNC) manually-operated interpolation generator with high precision, high surface smoothness, one can provides rational resolutions for all the foregoing problems.